Electric transformer



(No Model.) 2 Sheets-Sheet 2.

J. A. MOSHER. ELECTRIC TRANSPORMER. No. 543,346. I Patented July 23,1895.

y lllllll 3 :1' Z f UNITED STATES APATENT OEEICE.

JOHN A. MOSHER, OF CHICAGO, ILLINOIS.

ELECTRIC TRANSFORMER.

SPECIFICATION forming part of Letters Patent No. 543,346, dated July 23, 1895.

Application ilecl May '7, 1895. Serial No. 548,412. (No model.) v

To @ZZ whom it may concern:

Be it known that I, JOHN A. MOSHER, acitizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented certain new and useful Improvements in Transformers; and I do declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same, reference being had to the accompanying drawings, and to the letters and figures of reference marked thereon, which form a part of this specification.

The objects of my invention are to provide for the adjustment of the current to the requirements of the lamps vwhen in connection with the circuit without being obliged to depend upon resistance-coils or other means for supplementing the transformer; to increase the efciency of the magnetic core used in instruments of this class, and to provide simple means for entirely cutting out the trans-V former from the main line.

The invention consists of a peculiar construction of the core of the transformer, formed of two main sections, whereby the faces of the two sections are adapted to each other in such manner that a practically-perfect magnetic contact is secured throughout; and of a movable contact plug for the terminal block adapted to bring both terminals of the primary'coil into circuit with the main ine.

' In the dra-wings, Figure l represents an elevation of the transformer with its front plate or cap removed. Fig. 2 is an elevation of the inner side of this cap. Fig. 3 is a diagram of the wiring of the instrument. Fig. 4t is a vertical section on the line Il 4 of Fig. l. Fig. 5 is a transverse section on the line 5 5 of Fig. l. Fig. 6 is a bottom plan of the terminal block. Fig. 7 is a sectional View of the latter on the line 7 7 of Fig. 6. Fig. 8 is a detail of the contact-plug, and Fig. 9 is .an edge View of a plate forming one'of the laminations of the core.

-The transformer is contained in a metal box or case A, provided with suitable lugs for convenient attachment to any desired support, and having a removable front plate or cover B held in place by means of screwbolts h. The two sections of the core of the magnet are indicated at C D, the primary coil at E', and the secondary coil at E. I use a laminated core, forming a closed vmagnetic circuit. In order to form the core around the coils it is necessary that it bein sections. It has beenfound difficult in practice to bring the abutting faces of the several sections of such a core into the close contact necessary to secure its full efficiency. This difficulty is overcome by forming such faces oblique to the direction of their approach, so that as the several sections are forcibly drawn together the faces slide slightlyjone upon the other and the surfaces are brought into actual contact throughout their entire area.

The-form of the'plates may vary greatly and still accomplish the end in view. I show a simple form, which does not require expensive dies and in which the sections may be built up before adjustment to the case. As shown, each plate consists of the two sections C D. The former is U-shaped and has the inner edges of its arm beveled near their edges. The section D is trapezoidal in form and adapted to the widened mouth of the U.

The two sections of the core are built up to the desired thickness and secured, the one within the case A and the other to the inner surface-of the cover B. For the purpose of securing the portion C of the core to thecase, it is placed between rigid plates F F', which are held between the lugs G Gand G G, formed upon the inner surface of the case by means of binding-screws H passing through suitable apertures in one pair of these lugs. The section D is secured to the inner surface of the cover of the case by similar means, which need not be described. As shown, two cores are formed, one for each vertical side of the coils, though it is obvious that they could be united.

After the sections C of the core havebeen secured in position, the primary coil E is set within the recess formed in their faces. The secondary coil E is secured over the primary coil, and the sections D are closed over the two coils as the plate B is adjusted to the case. Thevscrew-bolts b provide means for drawing the opposing sections of the cores firmly IOO together, and their adjacent faces being inclined the pressure applied by means of these bolts secures a perfect contact throughout. This form of construction provides a core which is very simple and easily built up, and in which the magnetic circuit is practically as perfect as it would be were there no joints in the core.

The primary and secondary coils ar-e each inclosed in separate wrappings of their own, so that they may be separately adjusted. The case A is provided at its lower side with an extension J, which may be open at the bottom, as shown, and Within which is housed the terminal block L, which consists of a block of insulating material adapted to be secured within the case J to the lower side of the case A, which is suitably perforated for the passage therethrough of the binding-posts carried by the terminal block.

Referring now to the diagrammatic figure, the terminals of the main line are indicated at 1 l, of the primary coil at 2 2a. One of the ends of the secondary coil is permanently 'fixed at 3 and the other end at 3, intermediate terminals being shown at a, 5, 6, and 7.

To avoid confusionI have applied the same numerals to the binding-posts to which the several terminals are attached, as more plainly indicated in Fig. 6. An L.-shaped contactplate 8 is secured under the binding-post 1', a similar plate S being secured under the binding-post l. Similar plates 10 10a are Secured under the posts 2 2a. The pair of plates S 8 and the pair 10 10 rise from the face of the terminal block L in opposition to each other, and serve as clamps between which the plug M is inserted. The plug is provided with contact-plates 9 9 13 13N-two upon each side-adapted to engage respectively the plates 3,10, 8, and 10. The fusible wires 11 12 connect respectively the plates 9 il and the plates 13 13, passing through suitable apertures in the plug M. This arrangement of connection brings the two lines la 15 of the main circuit into communication with the primary coil E by means of 4a single plug, so that the instrument may be wholly cut outof circuit by simply removing the plug, thereby obviating the danger of accident from grounding, which is present when a separate plug is used for each terminal of the primary coil.

In taking the current from the transformer, if connection is made with either of the two binding-posts indicated at 3, and with the binding-post marked 3, the maximum voltage is secured. If less than the maximum voltage is required the connection is made with either one of the posts 4, 5, G, or 7, instead of with the post St. The terminals in connection with theseintermediate binding-posts spring from different turns of the secondary coil and supply currents of differing potentiality. By this arrangement the current may be adapted to each particular lamp, so as to compensate for loss from leakage or any peculiarity of the lamp itself without the loss that is incident to the use of a resistance-box or other supplemental adjusting agency.

In the diagrammatical iigure the voltage commonly employed in practice is indicated, the primary coil receiving one thousand volts, and the secondary coil delivering the maximum of fifty volts.

The plug M serves as a convenient location for the fusible wires ordinarily employed in connection with instruments of this class, and by thus placing the fuse of both wires oi' the circuit in a single plug repairs are much more easily made in case the fuse is burned out.

I claim as my invention- 1. The combination with the boxA having internal opposing lugs Gr, G', and binding screws carried by such lugs, and with the cover B having similar lugs and screws attached to its inner surface, of a sectional electro-magnet core whose members are adapted to be secured respectively between the lugs of the box and the lugs of the cover, said sections having co-operating contact faces whose planes are oblique to the direction of their approach, and of screw bolts for drawing the cover forcibly to the box whereby the opposing or cooperating faces of the core aro brought into contact, substantiallyl as described and for the purpose set forth.

2. In a transformer, the combination with the primary coil, of a terminal block for carrying the terminals of the primary coil and of the main circuit, of a contact plug adapted to connect both ends of the circuit with the primary coil.

3. In a transformer, the combination with the primary coil, of a terminal block having the binding posts 2, 2, for the attachment of IDO the terminals of the primary coil, and having contact plates 10, 10, and the binding posts 1, 1, for attachment of the terminals of the main circuit, and having the contact plates 8, S, and the plug M, having the electricallyconnected contact plates 9, 9, and the electrically connected contact plates 13, 13, the plates 9, 13, being adapted for contact with the plates 8, 8, and the plates 9, 13, being adapted for contact with the plates 10, 10, substantially as described and for the purpose specified.

4. The combination of the case A, having the removable cover plate B, the primary coil E', the secondary coil E, the sectional core, D, C, the contact faces of whose sections are transverse to the direction of the magnetic current and oblique to the direction of their mutual approach with the terminal block L, having a plurality of binding posts connected with different convolutions of the secondary coil and binding posts for the terminals of the primary coil and the main circuit and a contact plug for connecting the primary coil terminals and the main circuit terminals, substantially as described and for the purpose set forth.

5. In a transformer, the combination with a terminal block for attachment of the terminals of the primary coil andthe main circuit, of a contact plug for completing the circuit by connecting both wires of the main circuit With the primary coil, the medium of transmission through the plug being fusible, sub- 1o stantially as described and for the purpose specied.

In testimony whereof I afx my signature in presence of ltwo Witnesses.

. JOHN A. MOSHER. Witnesses:

Louis K. GILLsoN, W. T, BARTHOLOMEW. 

